Releasing and circulating overshot

ABSTRACT

A RELEASING AND CIRCULATING OVERSHOT WITH BASKET GRAPPLE AND PROVIDED WITH A CONTROL SPRING OPERABLE, UPON ROTATION OF THE OVERSHOT BOWL, TO URGE THE GRAPPLE BASKET INTO AND OUT OF CONTRACTED FRICTIONAL ENGAGEMENT WITH AN ASSOCIATED FISH. THE CONTROL SPRING IS OF THE HELICAL COMPRESSION TYPE AND SERVES TO MAINTAIN THE BASKET GRAPPLE AND BOWL IN RELATIVELY AXIALLY DISPLACED POSITIONS WITH THE BASKET GRAPPLE IN ITS UPPERMOST EXPANDED &#34;RELEASE&#34; POSITION WHILE THE OVERSHOT IS BEING PULLED UPWARD PAST TOOL COLLARS OR TOOL JOINTS WITHOUT ACTUATION OF THE BASKET GRAPPLE TO CATCH THE COLLARS OR TOOL JOINTS. THE SPRING ALSO SERVES TO ALLOW THE GRAPPLE TO BE SET, WHEN DESIRED, MERELY BY ROTATION OF THE BOWL RELATIVE TO THE BASKET GRAPPLE.

June 6, 1972 C. W. GRAY I BELEASING AND CIRCULATING OVERSHOT Filed Dec. 8, 1970 2 Sheets-Sheet 1 Fi i .T Hg .2

Claude M Gray INVENTOK.

BY MIA/WW6} m June 6, 1972 c. w. GRAY RELEASING AND CIRCULATING OVERSHOT 2 Sheets-Sheet 2 Filed Dec. 8, 1970 IN VENTOR WW Mikey W r G W m m United States Patent @fice 3,667,795 Patented June 6, 1972 3,667,795 RELEASING AND CIRCULATING OVERSHOT Claude W. Gray, K Fishing and Rental Tools, Inc., R0. Box 10131, Houma, La. 70360 Filed Dec. 8, 1970, Ser. No. 96,180 Int. Cl. E21b 31/02 U.S. Cl. 294-8617 9 Claims ABSTRACT OF THE DISCLOSURE A releasing and circulating overshot with'basket grapple and provided with a control spring operable, upon rotation of the overshot bowl, to urge the grapple basket into and out of contracted frictional engagement with an associated fish. The control spring is of the helical compression type and serves to maintain the basket grapple and Conventional releasing and circulating overshot assemblies, such as the Series 150 Releasing and Circulating Overshot with Basket Grapple marketed by Bowen Tools, Inc., of Houston, Tex., are for the most part fully capable of performing catching operations when an external catch is desired, unless for some reason the fish cannot be pulled upward such as when a packer does not release.

Although the aforementioned conventional overshot has incorporated therein means operable to effect its release, practice in the field has resulted in these conventional overshot tools not being capable of releasing with the result that an internal cutting tool must then be run down through the tubing below the overshot in order to remove the same. Further, conventional overshot assemblies may not be run in the washover pipe while sand is being cleaned out of the annulus defined above an associated packer because, if for some reason all of the sand was not washed out and it was desirable to come out of the hole, it would be impossible to do so. As soon as the wash pipe is elevated, the overshot grapple would latch onto the tubing and movement out of the hole would be impossible to pull because of the remaining sand on top of the packer, which sand would prevent release of the packer.

The overshot of the instant invention has been designed to provide a substantial positive means whereby its release may be eifected once it has been set should it become necessary to pull out of the hole. Further, the overshot of the instant invention may be reset at a higher elevation even after it has been set and subsequently released and therefore the overshot of the instant invention provides a more desirable and useful apparatus capable of performing several different operations in one trip including wash over, pulling and back-off operations.

The main object of this invention is to provide an overshot assembly including a substantially positive means for releasing the overshot once it has been set.

Another object of this invention, in accordance with the immediately preceding object, is to provide an overshot which may be subsequently again set after it has once been set and subsequently released without withdrawing the overshot assembly from the bore.

Still another object of this invention is to provide an overshot utilizing the basic structural features of conventional overshot mechanisms whereby the improved construction of the overshot of the instant invention will be for the most part familiar to workmen in the field.

A final object of this invention to be specifically enumerated herein is to provide an overshot assembly which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long lasting and relatively trouble free in operation.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is an elevational view of the overshot disposed within a well casing with the well casing illustrated in vertical section and a packe'r disposed in the well casing below the overshot;

FIG. 2 is an exploded perspective view of the overshot;

FIG. 3 is an enlarged top plan view of the basket grapple of the overshot;

FIG. 4 is a fragmentary enlarged vertical sectional view taken substantially upon the plane indicated by the section line 4-4 of FIG. 1 and with the basket grapple in a set condition;

FIG. 5 is a view similar to FIG. 4 but with the basket grapple in a release position;

FIG. 6 is a view similar to FIG. 4 but with the fore ground of the basket grapple broken away and illustrated in vertical section;

FIG. 7 is a horizontal sectional view taken substantially upon the plane indicated by the section line 7-7 of FIG. 4;

FIG. 8 is a horizontal sectional view taken substantially upon the alne' indicated by the section line 88 of FIG. 4; and

FIG. 9 is a perspective view of the overshot bowl with portions thereof being broken away and illustrated in vertical section.

Referring now more specifically to the drawings the packer 12 disposed therein through which a tubing string 14 extends; the tubing string 14 comprises a plurality of end-aligned tubing sections 16 joined together at adjacent ends by means of tubing collars 18 forming enlargements adapted to be engaged by the releasing and circulating overshot of the instant invention referred to in general by reference numeral 20.

The overshot 20 is carried by the lower end of a rotary washover string referred to in general by the reference numeral 22 and the lower terminal end of the washover string is provided with a rotary washover shoe 24. The string 22 comprises a plurality of end aligned and joined tubing sections 26 disposed above the overshot 20 and the washover shoe 24 is carried by the lower end of the overshot 20. v

The washover shoe and washover string 22 are of course designed to be utilized in washing sand out of the annulus disposed above the packer 12 and about the tubing string 14. The overshot 20 is constructed in a manner whereby it may be utilized as a part of the washover string 22 and run into the casing 10 with the washover string 22 including the washover shoe 24. When the washover string 22 has been utilized to wash sand out of the annulus disposed above the packer 12, the string 22 may be elevated so as to engage the overshot 20 with a tool joint or tubing coupling such as the coupling 18 before actuating the overshot 20.

The overshot 20 includes a lower hollow spring control bushing 28 including upper and lower externally threaded end portions 30 and 32. The bushing 28 is of course hollow and includes an upper end inner restriction 34 defining an upwardly facing circumferential abutmentshoulder 36.

The overshot 20 further includes a helical compression spring 38 whose lower end is abutted against the abutment shoulder 36 as well as a basket grapple control 40 including an upwardly projecting tongue or key 42.

The overshot 20 further includes a split collet type. basket grapple 44 having a lower end endwise outwardly opening notch 46 for receiving the tongue or key 42. The external surface of the grapple 44 is provided with helical left hand threads 48 including conical wedge surfaces 50. The cylindrical body of the grapple is rendered expansible and contractible by longitudinal slots forming a plurality of collet finger-type circumferentially spaced segments 52 whose free ends are disposed uppermost. The interior surfaces of the segments 52 are provided with longitudinally spaced inwardly projecting left hand threads 54 as shown in FIG. 6 and the upper free ends of the segments 52 are beveled and roughened as at 56.

The overshot 20 further includes a tubular overshot bowl 58 and an upper or top bushing 60. The upper end of the bushing 60 is internally threaded as at 62 for threaded engagement with the lower end of the lowermost tubing section 26 and the lower end of the top bushing 60 includes an externally threaded lower end portion 64 for threaded engagement with the internally threaded upper end 66 of the overshot bowl 58.

The overshot bowl 58 also includes an internally lower end portion 67 in which the threaded end portion 30 of the bushing 28 is engageable and further includes a circumferentially extending inner ridge 70 defining a downwardly facing abutment shoulder 72 against which the upper end face of the basket grapple 44 is engageable. In addition, the overshot bowl 58 includes internal helical threads 74 including cam surfaces 76 with which the cam surfaces or wedge surfaces 50 coact in a manner to be more fully set forth hereinafter in order to set the basket grapple 44.

As can be seen in FIG. of the drawings, the overshot 20 is in a release condition with the upper end of the grapple 44 held seated against the abutment shoulder 72 by the spring 38 in a compressed state with its lower end abutting shoulder 36 and its upper end abutted against the lower end face of the basket grapple control 40 while the upper end face of the grapple control 48 bears against.

the lower end face of the basket grapple 44. I

In operation, when it is desirable to set the basket grapple 44 on the tubing coupling 18, the washover string 22 is raised with basket grapple 44 until the upper end of the basket grapple 44 engages the lower end of the coupling 18 whereupon the grapple 44 will be slightly expanded at its upper end allowing the basket grapple 44 to slip upwardly over at least the lower end of the coupling 18 for frictionally gripping the lattenThen, the washover pipe 22 is pulled upward causing axial displacement of grapple 44 relative to bowl 58 against the bias of spring 38, whereupon the cam surfaces 50 and 76 contract the grapple 44 about the coupling 18 so as to prevent relative axial displacement between the grapple 44 and coupling 18. The upward pull on the washover pipe 22 is thus transferred to the coupling 18 and tubing string 14 in an effort to free the packer 12 and remove it from the hole or bore.

If the packer fails to release, two options are available to the operator that are not available to the operator using a conventional overshot. First, the operator can elect to remove the washover pipe 22 with the attached overshot 20 and second the operator can elect to perform a back-off operation.

As to the first option, the following procedure is'performed: the basket grapple 44 is disengaged from the tubing coupling 18 by lowering the washover string 22 into the hole. Then, the washover string 22 is elevated slowly until the basket grapple 44 again comes in contact with the tubing coupling 18. At this point, the washover string 22 is rotated to the right or clockwise as viewed in FIG. 7 while elevated slowly enabling the grapple basket 44 to be walked-over the tubing coupling 18 in a release condition as shown in FIG. 5. Inasmuch as the threads 54 are left hand threads rotation of the washover string 22 and grapple 44 clockwise prevents the teeth 54 from biting into the coupling 18. The release condition occurs because in assemblying the apparatus; the basket grapple 44 is screwed into the overshot bowl 58 and the basket grapple control 40 is placed directly next to the basket grapple 44 with the tongue 42 of the control 40 being inserted into the slot 46 of the basket grapple 44. Then, the spring 38 is placed directly next to the control 40. At this juncture, the spring control bushing 28 is screwed into the overshot bowl 58 compressing the spring 38 against the basket grapple control 40 which then keeps the basket grapple 44 frictionally retained in position in the overshot bowl 58. Also, because the coupling is attached to the tubing string 14 by right hand threads, rotation of the washover string to the right while the grapple is engaged with the coupling 18 tends to tighten it as the washover string 22 is rotated to the right and elevated relative to the tubing string 14.

After it has been determined that the packer 12 cannot be released by the force created by pulling upward on the washover string 22 subsequent to the basket grapple 44 engaging the coupling 18 as hereinbefore discribed, a wire line string-shot is lowered into the hole through the opening of the tubing string 14 and placed opposite the coupling 18 that the basket grapple 44 is engaged with. The use of string shots for the purpose of loosening threaded connections is well known as disclosed, for example, in U.S. Pat. No. 2,305,261 to Kinley. The operator will then rotate the washover string to the left imposing a torsional stress on the coupling 18 at the point of contact. After sufiicient force is exerted on the washover string, the string shot is fired causing the coupling 18 to back-off or unscrew from the tubing string 14 under the torsional stress.

The basket grapple 44 cannot walk-over the coupling 18 in the back-off operation as is done by rotating the washover pipe 22 to the right because the inwardly projecting teeth 54 are at an angle that causes the basket grapple 44 to engage the coupling 18 more firmly. Whereas, in the rotation to the right, the wallkover is achieved because the angle of the inwardly projecting teeth 54 allows the basket grapple 44 to be screwed or threaded over the coupling 18-.

It will be noted that the various outer tubular components of the overshot 20 comprising the bushing 28, the overshot bowl 58 and the top bushing 60, may all be constructed with substantially the same wall thickness and inner and outer diameters as the tubing sections 26. Accordingly, the overshot 20 can withstand the same tension as the washover string 22. In addition, as above set forth,

the overshot 20 may be set and subsequently released as many times as desired without pulling the washover string 22 from the casing 10. Further, inasmuch as left hand or counterclockwise rotation of the washover string 22 is required to set the basket grapple 44, the overshot 20 may be utilized to perform back-0E operations. Therefore, the overshot 20 may perform washing operations over the fish, may be utilized to pull the fish and may also be sired to perform a releasing operation, a sharp downward bump is required on the washover string for the purpose of attempting to cause axial displacement of an overshot bowl similar to the bowl 58 downward relative to a basket grapple similar to the grapple 44, which displacement is positively performed by the control spring 38 upon right hand rotation of the washover string 22. Accordingly, there are no failures encountered in attempting to release the basket grapple 44 after it has been set.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A washover overshot including a tubular body, a tubular basket grapple-type collet of the expandible and contractible type and including inner gripping surfaces for frictionally gripping a tool joint or tubing coupling disposed therein upon contraction of said collet from a static condition thereof, said body and collet including inner and outer threads, respectively, threadedly engaged with each other and provided with coacting wedge surfaces for contracting said collet upon rotation of the body in one direction relative to said collet, said body and collet further including means establishing a limit of axial shifting of said collet in a first direction relative to said body upon rotation of said body relative to said collet in said one direction, and means connected between said body and collet for yieldingly urging said collet in said first direction relative to said body.

2. The combination of claim 1 wherein said lastmentioned means comprises a helical compression spring disposed generally coaxially with said body and collet.

3. The combination of claim 2 wherein said threads on said body and collet are left hand and said spring is wound right hand, and means keying adjacent ends of said spring and collet together against relative rotation.

4. The combination of claim 3 wherein the last-mentioned means comprises a counterbored sleeve grapple control interposed between said adjacent ends keyed to said collet and in which the adjacent end of said spring is frictionally seated.

5. The combination of claim 1 wherein the end of said collet facing in said first direction is internally flared and includes friction gripping surface portions.

6. The method of selectively setting and releasing a basket grapple supported from a washover tubing string having an overshot bowl disposed therein in which the grapple is captively mounted for limited shifting along the string along the string, said method comprising the steps of establishing a threaded connection between the grapple and the bowl including coacting cam surfaces for contracting the grapple upon rotation of the bowl in one direction relative to the grapple, establishing a limit of axial shifting of the grapple relative to the bowl in a first direction upon rotation of the bowl relative to the grapple in said one direction, providing means operative to continuously bias said grapple in said first direction, and then rotating said bowl relative to said grapple in said one direction in order to set the grapple and in the opposite direction to release the grapple.

'7. A device for performing washover and pulling operations with respect to an elongated pipe having a plurality of axially spaced enlargements comprising a tubular body adapted to be positioned about the pipe, gripping means disposed within the body for engagement with the pipe in response to axial displacement of the body in one direction, means engageable with the gripping means for holding the gripping means disengaged from the pipe while being displaced between said enlargements in said one direction, means responsive to rotation of the body in one direction while the gripping means is engaged with one of the enlargements for releasing and gripping means to permit upward axial movement of the tubular body and the gripping means relative to the pipe and means responsive to rotation of the body in the other direction while engaged with one of the enlargements for imparting torsional stress to said one of the enlargements engaged by the gripping means.

8. The combination of claim 7 wherein said means for holding the gripping means disengaged includes an axial compression spring.

9. A method of performing washover, pipe pulling and back-01f operations relative to a pipe string having a plurality of pipe sections interconnected by threaded couplings, including the steps of: lowering a tubular washover body over the pipe string below a selected one of the couplings with an attached overshot gripping device rotatable in one direction for release; upwardly displacing the washover body to cause axial engagement between the gripping device and said selected one of the couplings; and rotating the body in the other direction while the gripping device is engaged with said selected one of the couplings to impart a torsional stress thereto tending to unscrew the same.

References Cited UNITED STATES PATENTS 2,970,859 2/1961 Justica 29486.17 2,616,752 11/1952 Osmum 294-86.l7 2,945,720 7/1960 Osmun 29486. l7

RICHARD E. AEGERTER, Primary Examiner J. D. CHERRY, Assistant Examiner US. Cl. X.R. 29486.22, 102R 

